In the production of recordings of music, lyrics and spoken words and in the transmission of the sonic signals related thereto, efforts have been made to present to a listener as close as possible a representation of the original sound.
In many processes the analog sound signals are digitized and reconverted to analog sound and equipment for playing the sounds and, generally, not capable of producing a true representation of the sonic signals as originally produced in musical presentations or ordinary speech. The equipment frequently, due to wear and other factors affecting ability of to reproduce the sounds is or becomes faulty, and efforts have been made to enhance the sound reproduced in various systems which limit the faithful reproduction of the original sound.
Much effort and development have been expended in the effort to improve the audio equipment including speakers and multichannel reproducing devices so as to distribute the sound waves in ways that are compatible with the sound perceptions of a listening audience.
All of these efforts are directed towards the goal of improving the quality of sound as presented to the listener.
The present invention is directed towards enabling adjustment of the quality of the sonic signals produced in sound transmission, listening, recording and playback of sonic signals, by adding to the signals desirable characteristics either not played or which improve the sound received by adding reverberation or echo effect, balancing the phase of the signal and adding second harmonics.
This invention in one sense relates to systems for playback, transcription and transformation of sonic signals, and more particularly to systems for transforming sonic signals fed through headphone type output circuit means including means for increasing, maintaining, or decreasing the impedance to such signals received from sonic signal headphone output circuit means and for passing the signals, after adjusting the impedance to them, as necessary, through microphone type input means or recording input circuit means which are included in a playback or record/playback means for sonic signals such as a magnetic tape cassette deck or a video. cassette recorder (VCR) or a compact disc player.
In preferred embodiments, these systems include headphone means that can be linked to the headphone output means of a system for playback and recording of sonic signals. Preferably, such headphone means include means for increasing and/or decreasing the impedance to sonic signals from sonic signal headphone output means. Such increasing/decreasing means is preferably an adjustable potentiometer that can provide at least 200 ohms, preferably at least 5 kilo ohms in resistance to sonic signals from the headphone output means. Such headphone means can also include speaker means to which the sonic signals pass from the potentiometer then pass to sonic signal microphone input means or sonic signal recording input means, either directly from the potentiometer means or from the potentiometer means, via sonic signal headphone speaker means to the microphone input means or recording input means.
In some embodiments, the sonic signal transforming means of this invention is linked, at one end, to the headphone output means for a sonic signal record/playback device such as a magnetic tape cassette deck and, at the other end, to the microphone input means or recording input means or even speaker means such as a magnetic tape playback record means, a VCR or a compact disc player.
In these embodiments,the signal-to-noise ratio of the sonic signals coming from a source such as magnetic tape, a radio, a record player, or compact disc player can be improved by adjusting the means for controlling the sonic signal level output from the system including the headphone output means, and/or by adjusting the means for controlling sonic signal level input to the system including the microphone input means or recording input means.
Preferred embodiments of such systems can permit the sonic signal output level from the headphone output circuit means to be as low as minus 71 decibels and the input level at the microphone input circuit means as high as plus 9 or 10 decibels. By appropriate adjustment of the signal level at the headphone output circuit means, and at the microphone input circuit means or recording input means, signal-to-noise ratio in sonic signals to be played back or transcribed can be substantially improved with substantially no reduction in fidelity or quality.
Preferred embodiments also include systems which are self contained, say in a stereophonic tape or disc player device, or other devices in which self contained systems for enhancement of analog or stereophonic sound is desired.